A pot experiment was carried out to explore the growth and photosynthetic characteristics of 7 island cotton varieties (including XH16,XH20,XH24,XH25,XH28,XH34 and XH35) under salt stress (0.6％ NaCl),so as to provide a theoretical basis for the cultivation of island cotton and breeding of salt-tolerant varieties.The results showed that,under 0.6％ NaCl salt stress,the germination rate,plant height,fresh weight per plant,dry weight per plant,chlorophyll content (Chl),net photosynthetic rate (Pn),intercellular CO2 concentration (Ci),stomatal conductance (Gs) and transpiration rate (Tr) were decreased,while the plant water content,soluble sugar (SS) content,soluble protein (SP) content and malondialdehyde (MDA) content were increased.Under the same condition of salt stress,the plant water contem and MDA content were lower while the content of SS and SP were higher in XH24,XH34,XH28 and XH35 than those in the other 3 varieties,showing a good tolerance to salt stress.It was also found that 0.6％ NaCl salt stress affected the height,fresh weight,dry weight and water content of seedlings more than the seed germination rate of island cotton.The decrease of net photosynthetic rate in leaves of island cotton seedlings might be caused by stomatal limitation factors.All the tested island cotton varieties showed a rather good tolerance to salt stress,except for XH20.%采用盆栽试验方法,研究了新海16号、新海20号、新海24号、新海25号、新海28号、新海34号和新海35号等7个海岛棉品种在盐胁迫(0.6％ NaCl)下幼苗生长情况、光合特性等,为海岛棉栽培管理及耐盐品种的选育提供一定的理论依据.结果表明,0.6％ NaCl盐胁迫下,种子出苗率、株高、鲜重、干重、第一片真叶叶绿素含量(Chl)、净光合速率(Pn)、胞间CO2浓度(Ci)、气孔导度(Gs)和蒸腾速率(Tr)均有所下降;而植株含水量、可溶性糖含量(SS)、可溶性蛋白质(SP)和丙二醛含量(MDA)均增加.同等盐胁迫条件下,新海24号、新海34号、28新海号、新海35号与其余3个品种相比,具有较低的植株含水量和丙二醛含量,均保持较高的可溶性糖含量和可溶性蛋白质含量,表现出较好的耐盐性.本研究发现,0.6％ NaCl盐胁迫对海岛棉种子出苗影响较小,对幼苗株高、鲜重、干重和植株含水量影响较大.海岛棉幼苗叶片净光合速率降低可能是气孔限制因素所引起的.海岛棉品种在0.6％NaCl盐胁迫下基本上都表现出较好的耐盐性,但对新海20号的影响较大.
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